Medicine

Over-the-counter drug (OTC): definition, regulation, and safe use Over-the-counter drug An accessible overview of over-the-counter drugs: what they are, common types and uses, regulatory frameworks, safety considerations, and distinctions such as pharmacist-only produ…

Overdose (drug poisoning): causes, effects, and emergency response Overdose An overdose happens when intake of a drug or chemical exceeds the body's ability to tolerate it. Covers causes, signs, immediate treatment, prevention and distinctions between acci…

Overweight: definition, measurement, causes, health effects and social aspects Overweight Overview of overweight as a condition of excess body fat, how it is measured, common causes, associated health risks and social implications, plus limits of measurements and approa…

Oxycodone: overview, properties, uses, history and safety Oxycodone Oxycodone is a semi-synthetic opioid analgesic used to treat moderate to severe pain. This article explains how it works, common formulations, history, risks, and distinctions from…

Oxygen therapy: definition, delivery methods, uses, risks and history Oxygen therapy Supplemental oxygen is medical O2 given to raise blood oxygen levels. This article explains how it’s delivered, common indications, monitoring and safety considerations, and a brie…

Padded cell (psychiatric seclusion room) Padded cell A padded cell is a specially designed room used in psychiatric care to protect patients during extreme agitation, seizure, or crisis. This article explains its purpose, design, his…

Paget's disease: bone, mammary and extramammary forms Paget's disease Concise overview of Paget's disease covering the main forms (bone, mammary, extramammary), causes, clinical features, diagnosis, treatment approaches, complications and historical…

Pain: nature, causes, types, and management Pain An accessible overview of pain: biological mechanisms, common types, clinical assessment and treatments, and the distinction between nociception and the subjective experience.

Pain disorder (psychogenic chronic pain) Pain disorder Chronic pain in which psychological factors are judged to have a major role. Covers symptoms, diagnosis, causes, treatments (therapy, medications, multidisciplinary care) and disti…

Painful sexual act (dyspareunia): causes, diagnosis, and management Painful sexual act Painful sexual act, medically called dyspareunia, is pain in the genital area before, during, or after sexual activity. Causes may be physical, psychological, or both; management i…

Pallor (paleness): causes, signs, mechanisms and when to seek care Pallor Pallor is an observable paleness of the skin and mucous membranes caused by reduced blood flow or lower hemoglobin. This article explains signs, common causes, underlying mechanism…

Palmar (Volar) Plate: Anatomy, Function, and Clinical Significance Palmar plate A concise overview of the palmar (volar) plate — a fibrocartilaginous structure on the palmar side of finger joints that stabilizes, guides motion, and resists hyperextension; incl…

Pancreatic cancer: overview, symptoms, diagnosis, treatment, and prognosis Pancreatic cancer Pancreatic cancer is a malignant disease of the pancreas with a historically poor prognosis. This article summarizes types, symptoms, diagnosis, staging, treatment options, risk fa…

Pancreatitis: causes, symptoms, diagnosis and treatment Pancreatitis Pancreatitis is inflammation of the pancreas causing abdominal pain and digestive/hormonal disruption. This article explains types, causes, typical symptoms, diagnosis, treatments,…

Pancuronium bromide Pancuronium bromide is a long-acting non-depolarizing neuromuscular blocker used in anesthesia for muscle relaxation; it is also known for use in lethal injection and euthanasia pr…

Pantothenic acid (vitamin B5) Pantothenic acid Pantothenic acid (vitamin B5) is a water-soluble B vitamin essential for creating coenzyme A and for energy and fatty-acid metabolism. Found widely in foods; deficiency is rare.

Paracetamol (acetaminophen): uses, mechanism, safety and history Paracetamol Paracetamol (acetaminophen) is a widely used analgesic and antipyretic for pain and fever. This article summarizes names, chemistry, mechanism, clinical uses, formulations, safety,…

Paralysis: causes, types, diagnosis, and management Paralysis Paralysis is the loss of voluntary muscle function because of nervous system injury or disease. This article summarizes types, common causes, clinical features, diagnosis, treatmen…

Paramedic: role, training, skills and place in emergency medical services Paramedic An overview of paramedics: their responsibilities, training, scope of practice, relationship to other ambulance staff, history and importance in emergency care.

Paraphilia: definition, examples, clinical perspective and social context Paraphilia Overview of paraphilia: definitions, common types, diagnostic distinctions, history, treatment approaches, legal and cultural considerations, and links to related topics.

Paraplegia: causes, features, classification, and rehabilitation Paraplegia Paraplegia is loss of motor and/or sensory function in the lower half of the body, most often due to spinal cord injury or disease. This article explains causes, types, diagnosis,…

Parathyroid hormone (PTH) Parathyroid hormone Parathyroid hormone (PTH) is a peptide hormone from the parathyroid glands that maintains blood calcium by acting on bone, kidney and vitamin D metabolism; abnormalities cause hypo…

Paratyphoid fever A systemic enteric infection caused by Salmonella paratyphi species. Similar to typhoid fever, it spreads by fecal–oral contamination, causes prolonged fever and abdominal illness,…

Paresthesia — the sensation of tingling, prickling, or numbness Paresthesia Paresthesia is an abnormal sensation—commonly "pins and needles"—that can be transient or chronic. Causes range from pressure on nerves to metabolic, toxic, or neurological conditi…

Parkinson's disease A progressive neurodegenerative disorder that primarily affects movement and multiple non-motor functions, caused by loss of dopamine-producing neurons and characterized by tremor,…

Parkinsonian syndrome: causes, features, diagnosis and management Parkinsonian syndrome Parkinsonian syndrome (parkinsonism) is a clinical syndrome of tremor, slowness, rigidity and balance problems with many causes beyond Parkinson's disease; diagnosis and treatment…

Paroxetine (Paxil): overview, uses, effects and safety Paroxetine Paroxetine is an SSRI antidepressant used for depression and several anxiety disorders. This article explains what it does, common side effects, safety concerns, and practical pres…

Pathology: the medical study of disease and diagnosis Pathology Pathology is the medical science that investigates disease causes, mechanisms and effects through examination of tissues, fluids and organs; it underpins diagnosis, prognosis, rese…

Patient (medical): definition, types, rights, and patient-centered care Patient A patient is a person receiving or awaiting medical care. This article explains meanings, settings, categories, rights and responsibilities, and the role of patient-centered care a…

Pediatrics: medical care for infants, children and adolescents Pediatrics Pediatrics is the medical specialty focused on the health, growth and development of infants, children and adolescents, emphasizing prevention, diagnosis, treatment and family-cent…

Pedicure: Cosmetic and hygienic care of the feet and toenails Pedicure A pedicure is a cosmetic and hygienic treatment for feet and toenails that includes trimming, exfoliation, callus removal and often polish. It has practical benefits, cultural hist…

Pellagra: causes, symptoms, history, prevention and treatment Pellagra Pellagra is a clinical syndrome caused by deficiency of niacin (vitamin B3). This article explains causes, classic signs, history, diagnosis, treatment, prevention and public‑healt…

Pelvic inflammatory disease (PID) Pelvic inflammatory disease Pelvic inflammatory disease is an infection of the female reproductive organs that can cause pain, infertility, and other complications. It is usually bacterial and often treatable…

Penicillin: discovery, properties, uses, resistance and safety Penicillin Penicillin is a foundational group of beta-lactam antibiotics derived from Penicillium fungi; it revolutionized medicine, treats many bacterial infections, but faces resistance and…

Penile cancer: overview, causes, diagnosis, and treatment Penile cancer Penile cancer is an uncommon malignancy of the penis. This article explains its characteristics, risk factors, diagnosis, treatment options, prevention, and public-health considera…

Peptic ulcer: causes, symptoms, diagnosis and treatment Peptic ulcer A peptic ulcer is a sore in the stomach or first part of the small intestine. This article explains causes, symptoms, diagnosis, treatment, and differences between gastric and duod…

Periodontitis — inflammatory disease affecting the tissues around teeth Periodontitis Periodontitis is a progressive inflammatory disease that destroys the tooth-supporting tissues (periodontium), causing pocketing, bone loss and possible tooth loss. Management emph…

Peripheral artery disease (PAD): causes, symptoms, diagnosis and management Peripheral artery disease Peripheral artery disease (PAD) is narrowing of arteries that supply the limbs—most often the legs—causing pain on walking, poor wound healing and increased cardiovascular risk.

Peripheral neuropathy: causes, patterns, symptoms and management Peripheral neuropathy Peripheral neuropathy is nerve damage outside the brain and spinal cord causing sensory, motor or autonomic symptoms; causes, evaluation, and common treatments are explained.

Peritonitis: inflammation of the abdominal lining — causes, signs, and care Peritonitis Peritonitis is inflammation of the peritoneum, usually from infection or organ rupture. It causes severe abdominal pain, fever, and tenderness and often requires urgent antibiotics…

Pernicious anemia: causes, symptoms, diagnosis, and treatment Pernicious anemia Pernicious anemia is a vitamin B12 malabsorption disorder caused by loss of intrinsic factor, leading to megaloblastic anemia and neurologic symptoms; it usually requires lifelong…

Pertussis (Whooping Cough): Causes, Course, Prevention, and Public Health Pertussis Pertussis, or whooping cough, is a highly contagious respiratory infection caused by Bordetella pertussis. This article explains symptoms, stages, complications, diagnosis, treatme…

Pestilence: meaning, history, and public‑health implications Pestilence Pestilence: the historical and modern use of the word for highly infectious diseases, its characteristics, major outbreaks, and how societies respond and remember such events.

Pethidine (Meperidine): an overview of the opioid analgesic Pethidine Pethidine (meperidine, Demerol) is a synthetic opioid analgesic used for acute moderate to severe pain. It produces typical opioid effects, has a neurotoxic metabolite, and importa…

Phalanges: Structure, Function, and Clinical Significance Phalanges Phalanges are the small bones of the fingers and toes. This article explains their anatomy, development, roles in hand and foot function, common injuries and variations, and notabl…

Pharmacist A pharmacist is a licensed health professional who prepares and dispenses medicines, advises patients and clinicians on safe and effective drug use, and manages medication therapy…

Pharmacology: the science of drugs and their effects on living systems Pharmacology Comprehensive overview of pharmacology: definitions, core principles (pharmacokinetics and pharmacodynamics), history, drug development, clinical applications, and distinctions fro…

Pharmaconomist: Danish pharmacy practitioner and medicines specialist Pharmaconomist A pharmaconomist is a professionally trained Danish pharmacy practitioner who dispenses medicines, counsels patients, manages pharmacy operations and supports medicine safety. Dist…